Multiple-axis folded optical system for a photographic camera



NSV J. G. EAKR Bp MULTIPLE-AXIS FOLDED OPTCAL SYSTEM FOR A Pamoempmc CAMERA Filed im. l5, 196e r-l i e l E?? Q s Q Q l 36 Q Q Q .Q g Q Q @f ass d?? INVENTOR 50mm 5, ww,

a/w 1w/m amff ATTORNEYS A n l .f1

, sns-trasse z natale-Artis nomen onerose svariate it praesentiert-nc earner-ta llames G. halter, Winchester, Mass., assigner to lolaroid Compradora, @ela-vare Filed Dec. l5, i966, Ser. No. Silld int. iCl. Gmb 37/02 US. tCl. 95--l5' BS'EIRC @lll THE DISCLOSURE A compact; non-folding photographic camera embody- Qamhridge, Mass., a `corptunatien of S Claims i ing a folded optical system. The camera includes a relatively long focal length objective lens structure for imaging a scene upon a photosensitive material within the camera. Thefolded optical system for folding the exposure light path from the scene to the photosensitive i material comprises a plurality of light reflective surfaces l arranged to dellect the exposure light path successively 1 along three substantially mutually orthogonal axes to 1 permit not only the depth dimension but also either the width or length dimension of the camera to be especially compact.

Caoss REFERENCES To RELATED APPLICATIONS i A compact camera is disclosed in a copending applicai tion of Edwin H. Land, Ser. No. 549,961, tiled May 3l, 1966 (now U.S. Patent No. 3,405,619, issued Oct. 15, 1968), which has a front-to-back depth dimension which Cil is small in comparison with the focal length of the objective lens means which maybe used and in relation to the usable hlm format size. In order to obtain such a comt pact camera, the exposure light path is folded along two mutually orthogonal axes parallel to the length and depth dimensions of the camera. -The photosensitive material is exposed incrementally but continuously while being transported behind an elongated focal plane aperture. Means are provided for causing the image formed by the objective lens means to move with the photosensitive material during exposure so as to remain substantially stationary with respect thereto.

OBJECTS It is an object of this invention to provide an improved compact camera in the general nature of the camera described above having an optical system by which the cxposure light path may be compactly folded so as to accommodate an objective lensl means-having a long focal length in a very compact volume.

It is another object to provide a compact camera in- .cluding in its optical system a plurality of light reflective surfaces arranged to deflect the exposure light path successively along at least two substantially mutually orthogonal axes to permit not only the depth dimension but also either the width or length dimension of the camera to be especially compact.

SUMMARY OF THE INVENTION The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which arc cxcmplilcd in thc followl t ing detailed disclosure, and the scope of the application of which will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWING For a fuller understanding of the nature and objects of the invention, reference should be had to the follow ing detailed description taken in connection with the accompanying drawing wherein the gure is a perspective view of a photographic camera lwhich might be constructed in accordance with the principles of the invention. The camera housing is shown in phantom lines in order to clearly illustrate the internal structures. Certain components of the camera which are not necessary t0 the understanding of the present invention have been omitted in the interest of clarity and simplicity.

ln cameras constructed in accordance with this invention, a relatively large film format and a correspondingly long focal length obiective lens can be accommodated in a compact non-folding camera having a housing which is especially compact in the front-to-baclt dimension, referre( to hereinafter as the depth dimension.

DESCRIPTION OF THE PREFERRED EMBODMENTS The drawing depicts a photographic camera incorporating embodiment of the invention, the camera including a housing lll defining a generally rectangular volume having a minor depth dimension substantially smaller than major length and width dimensions thereof. The camera may include a variable diaphragm il and objective lens means for forming an image of the scene on a sheet 12, of photosensitive material. Although numerous suitable objective lens structures may be devised, for clarity of illustration of the invention a simple two-element achromatic lens 16 is shown to represent the image` forming means for the camera.

In order to accommodate a long focal length imageforming lens in such a compact camera, optical means are provided in accordance with the present invention for folding the optical path from the scene to the photosensitive material. As taught in the above-identified copending application of E. H. Land, a long focal length lens and a large lm format may be accommodated in a compact camera by causing the photographic image to be formed through an elongated focal plane aperture i8 in a masi: 20 in an image plane immediately behind and parallel to the mask 2t). Means are provided for simultaneously scanning the scene in coordination with a transport of the film in the image plane behind the aperture i3. With a proper coordination of the scan of the scene and the transport of the lm, the image of the scene formed on the photosensitive sheet may be rendered stationary relative to the moving sheet l2.

An optical system constructed in accordance with this invention may, as in the preferred embodiment illustrated, comprise a plurality of light retlective surfaces arranged to successively deflect the exposure light path from the scene sequentially along three substantially mutually orthogonal axes and through thc focal plane aperture i8 to the photosensitive sheet 12. The optical structure for thus operating on exposure light path may include a. planar mirror 22 disposed in the path of light incident from the scene along an axis parallel to the depth dimension of the housing l0, hereinafter termed the Z-Z axiS. The mirror 22 is oriented at approximately 45 to the Z-Z axis so as to deflect the light path along a second axis, the X-X axis, substantially orthogonal to the Z--Z axis and parallel to the width dimension of the housing itil.

A second planar mirror 2d is disposed in the exposure light path on thc X-X axis at an angle of approximately 45" with respect thereto so as to deflect thc light path along :in axis, the Y-Y axis, parallel to the length c) f.: 0741-. "n w dimension or" housing it@ and substantially ortho! anal to the iff-X and Z-Z axes. ',i`he mirror O5-, in addition to producing a reversal of the image fo ned by the lens liti, effects the 90 rotation of the image necessary in order that a horizontal seau of the scene may he harmonized with a transport of the photosensitive sheet i2 in a direction orthogonal to the direction of the scan o the scene.

A tnird planar mirror is disposed adjacent the l'ocal plane aperture ld and on the Y-Y axis. The mirror 6 is oriented at approximately 45 with respect to the Y--Y axis to defi-ect the light path along an axis, .Z1- El, paralici to the IZ-Z axis and through the aperture lt is evident from the drawing and the above description that the masi; 2d and the limited effective horizontes? held angle of the described optical system permit at any instant onlyr a narrow segment of the scene being photographed to be formed upon the photosensitive sheet i12. So that a complete image of the scene may be formed on the photosensitive sheet during an exposure interval, means are provided for simultaneously, and in coor dination, transporting the photosensitive sheet while causing the optical system to scan the scene being photogr'apncd.

lAs indicated in the above-identified patent application of E. H'. Land, the transportation of the photosensitive sheet relative to the exposure aperture during exposure acts as a shutter by determining the interval during .hich cach increment of the photosensitive sheet il?. is exposed to ectinic light from the scene. ri`he duration of exposure of any incremental area of the photosensitive slicet is a function of the aperture width and the speed of movement of the sheet i2. past the aperture lf3. The total time required tomalte a complete exposure of the sheet tft depends upon the length of the portion of the sheet which isto be exposed and the speed at which the sheet l?. is transported during exposure. Por example, an arca of :t sheet three inches in length may be subjected to an exposure of lfm second Dy moving the sheet past an aperture .l5 inch v/ide at a rate of nine inches per second with a total time required for exposure of l/3 second.

lt is noted that the width of the aperture in no way affects the intensity of the exposure light admitted to the photoscnsitive sheet i2, but rather is one factor in determining the effective exposure interval. The diaphragm Elli serves the conventional f-number and depth-of-fielddetermining functions of a stop.

Numerous methods and means may be employed for effecting such a simultaneous scan of the scene and trans* port of the hlm materials, the drawing showing one illustrative example representative of the many structures which may be employed for performing this act.

Structure for effecting a constant speed transport of the photoseusitive sheet behind the aperture iii in mask ZS may comprise a pair of sprockets 28, 3G on a shaft 32. driven by a motor which may, for example, hc either batteryor spring-powered. rl`he sprockets 2.3 engage suitable perforations in the photosensitive sheet i?. for moving the sheet l2 at a rate dependent upon the speed of the motor 3d.

In order that a scan of the scene may be achieved in coordination with a transport of the photosensitive sheet 12, means may be provided/for rotating the mirror 22 during exposure. Such means for rotating mirror 22. may comprise a yoke supporting the mirror 22 for rotation upon a shaft 40. A set of worm gears (i2, 43 driven oft shaft 32 may he utilized to rotate a radial cam 4d on a cam-carrying shaft 46. A transverse arm on shaft di) is adapted to engage a suitably shaped cam dll in order that rotation of thc drive shaft 32 to drive the sheet il?. may bc coordinated with rotation of the mirror 27, on shaft Iii).

By a proper design of the configuration of cam dfi, the gear ratio of the worm gears d2, d3, the location of the pivot axis of the shaft with respect to the location and angular orientation of the mirror 2?., and the various other pertinent parameters involved, the scan of the scene ocingphotographed and the transport of the photosensitive sheet may he precisely coordinated such that the successive imaging of adjacent increments or the scene on the moving photosensitive sheet l2 during exposure results in a complete and accurate image of the scene being formed on the sheet "VZ, The ligure reprer nts 'the camera 's it might appear if stopped at an instant during exposure.

it is evident that by this invention optical means have heen provided with which a long iocal length objective lens meahs and a correspondingly large film. format may be accommodated in an'extremely compact, non-folding camera.

Certain changes may be made in the above apparatus without departing from the scope of the invention herein involved. For example, any or all of; the illustrated iight reflective surfaces may be provided by totat reflection prisms rather than mirrors such as are illustrated at 2.2,

and Z6.

An Amici or root` prism may he located on the 'Zr-Z axis in substitution for mirror or on the X-X axis in substitution for mirror is noted that the substitution or a 45 inclined roof or Amici prism at either of these locations would have the effect of producing an additional reversal of the image while preserving the orthogonal relationship of the axes or' thc incident and reected light.

It is noted that the light reliective means incorporated in the exposure optics of the illustrated embodiment of the invention effect an Odd number of reversals of the image formed on the photosensitive sheet i2. it is evident that, for development by conventional processes, the negative image would have to further reversed an odd number of times to produce an accurate erect image of the photographic subject. An embodiment constructed without a third reflective surface, such as mirror 2d, vto deflect the exposure light parallel to the .'.Z--Z axis, or one employing a roof prism in place of either of mirrors 2.2 and 2d, as suggested above, would require no such subsequent reversal of the negative image.

Whereas an optical system has been shown in which the exposure light path is introduced .into the camera near the upper left-hand corner thereof, the invention contemplates a system constructed such that the light path enters the camera housing adjacent the upper right-hand corner thereof. The attitude of mirrors and 2d would, of course, have to 'oe altered accordingly. As a further alternative, the mirror 26 might, he rotated 90 about its lengthwise axis to deflect the optical path into impingement with photosensitive material behind an exposure aperture parallel to the illustrated aperture iii) but iocated near the front, rather than the rear, wall of the housing lli).

As suggested above, in another embodiment of the invention the mirror 26 may he eliminated and the exposure effected through a focal plane exposure aperture disposed nearv the lower end of the housing in a piene purallcl to the width and depth dimensions ot the camera. it is evident, of course, that such an arrangement would require means different than illustrated for transporting the sheet 312 past the exposure aperture. it should be understood that other arrangements of light reflective surfaces may be devised within the teachings and purview of this invention.

As a still further example, of structures encompassed by this invention, whereas a simple two-element achromat has heen shown positioned forwardly of the mirror 22, it should be understood that other more complex imageformng means may be used and that the image-forming means may be located in other parts ot the optical path from the scene to the image plane. It is therefore intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

El. A compact photographic camera for exposing photosensitive material positioned initially in a predetermined plane within the camera, comprising, in combination:

means defining an elongated focal plane aperture adjacent the photosensitive material;

lens means for imaging a scene upon said photosensitive material through said focal plane aperture; means for effecting relative movement during exposure between said photosensitive material and said aperture for sequentially exposing adjacent areas of said photosensitive material through said aperture; means for effecting relative movement during exposure between the scene image formed by said lens means and said aperture so as to maintain said image stationary with respect to the photoscnsitive material; and

optical means for folding the light path from thef scene to the photosensitive material along three successive substantially mutually orthogonal axes, the second and third axes are parallel to the plane of the photosensitive material.

2. 'Die apparatus defined by claim l wherein said optical means comprises a plurality of light reflective surfaces arranged to successively deflect the exposure light path along said three axes.

3. A compact photographic camera for exposing photosensitive material within the camera, comprising, in combination:

means defining elongated focal plane aperture adjacent the photosensitive material;

lens means for imaging a scene upon said photosensitive material through said focal plane aperture;

means for effecting relative movement during exposure between said photosensitive material and said aperture for sequentially exposing adjacent areas of said photos'ensitive material through said aperture; means for effecting relative movement during exposure between the scene image formed by said lens means and said aperture so as to maintain said image stat tionary with respect to the photosensitive material;

a first planar light reflective surface oriented at approximately 45 with respect to light incident from the scene along a first axis so as to deflect the light path along a second axis substantially orthogonal to said first axis, and parallel to said photosensitive material;

a second planar light reflective surface disposed on said second axis and at an angle of approximately 45 thereto so as to deflect the light path along a third axis substantially orthorgonal to said first and second axes, and parallel to said photosensitive material,

a third planar light reflective surface disposed on said third axis and at an angle of approximately 45 thereto so as to deflect said light path in a direction substantially parallel tosaid first axis and through said aperture in said aperture means.

fi. A compact photographic camera for exposing a photosensitive material in the camera comprising, in combination:

a housing having orthogonal depth, width and length axes;

lens means for imaging a scene upon a photosensitivc material in a plane defined by said length and width axes;

means for defining an elongated focal plane aperture adjacent the photosensitive material;

means for effecting relative movement during exposure between said photosensitive material and said aperture for sequentially exposing adjacent areas of said p'hotosensitive material through said aperture;

light reflective means for folding the light path from thc scene to the photosensitivc material, comprising a plurality of light reflective surfaces arranged to successively deflect the light path along three successive substantially mutually orthogonal axes and through said aperture; and

ieans including at least a part of said light reflective means for effecting a scan of the scene during exposure to produce a movement of the scene image relative to said aperture at a rate effective to maintain said scene image stationary with respect to the photosensitive material.

5. A compact photographic camera for exposing a photosensitive material in the camera comprising, in combination:

a housing having orthogonal depth, width and length lens means or imaging a scene upon a photosensitive material located. initially in a plane defined by said length and width axes;

' means for defining an elongated focal plane aperture adjacent the. photosensitive material;

means for effecting relative movement during exposure between said photosensitive material and said aperture for sequentially exposing adjacent arcas of said photosensitive material through said aperture;

a first planar mirror in the path of light from the scene being photographed, said first mirror being oriented at approximately 45 with respect to said depth axis so as to deflect the light path in a direction substantially along said Width axis,

a second planar mirror disposed in the light path at an angle of approximately 45 with respect to said width axis so as to deflect the light path in a direction substantially along said length axis, and

a third planar mirror disposed in the light path at an angle of approximately 45 with respect to said length axis so as to deflect said light path in a direction substantially along said depth axis and through said aperture;

means including at least one of said planar mirrors for effecting a scan of the scene during exposure to produce a movement of the scene image relative to said aperture at a rate effective to maintain said scene :mage stationary with respect to the photosensitive material.

6. A compact photographic camera including a housing defining a generally rectangular volume having a minor depth dimension substantially smaller than major length and width dimensions thereof;

means defining an elongated focal plane exposure aperture eccentrically positioned within said housing; means for supporting a sheet of photosensitive material whose width and length are greater than said depth dimension, within said housing and for transporting said sheet in a plane parallel to the plane dehned by said length and width dimensions and past said exposure aperture at a predetermined velocity; means located adjacent one corner of said rectangular volume for admitting light from a scene to be photographed to the interior of said housing along a iirst optical axis generally parallel to said depth dimension and perpendicular to the plane of said photosensitive material; light reflective means for folding the optical path along two additional axes, mutually orthogonal to each other and parallel to said plane of said photosensitive material, from said means for admitting light into said housing to said exposure aperture; lens means for focusing light from said sccnc as an image on the surface of said photoscnsitive material; and V means for causing said lens means to scan said scene in synchronism with thc movement of said photosensitive material past said exposure aperture to maintain said image stationary with respect to said photosensitive material.

' 7. A compact photographic camera including a housing defining a generally rectangular volume having a minor depth dimension substantially smaller than major length and width dimensions thereof;

within said housing; and for transporting said sheet past said exposure aperture at a predetermined velocity;

3,475,652 il l mejins defining an elongated focal plane exposure apermeans located adiacenti one corner of said rectangular ture eccentrically positioned within said housing; volume for admitting light from a scene to be photomeans for supporting a sheet oi4 photoscnsitive material graphed to the interior of said housing' eong a first within 4said housing and for transporting said sheet optical axis generally parallel to said depth dimension', past said exposure aperture at a predetermined veloe-V rst reflector means antgularly oriented with resa/cet to l ity; said rst optical axis to intercept light passing through 'means located adjacent one corner ot: said rectangular said diaphragm means and reflect it along a second volume for admitting light from a scene to be photooptical axis generally orthogonal to said first optical graphed to the interior of said housing along a first axis; optical axis generally parallelto said depth dimension; IU second reflector means angularly oriented. with respect first reflector means angularly oriented with respect to to said second optical axis to intercept light passing said first optical axis to intercept light passing through along said second optical axis and reflect lt along a said diaphragm means and reflect it alongT a second third optical axis generally orthogonal to said first @P15031 HXS SGncfally OflhOtlOttl l0 Silld YS OPlCZil and second optical axes toward said xposure aperaxis; 1 ture;

second reflector means angular-ly oriented with respect third reflector means angularly oriente/tl with respect to to said second optical axis and approximately parut said third optical axis to intercept light passing atom; tel to said first axis to intercept light passing along said third optical axis and rellect it along;7 a 'fourth said second optical axis and reflect it along a third optical axis generally parallel to said first optical axis optical axis generally orthogonal to both said first u toward Said exposure aperture; and Second Optical aXCS OWafd Suid CXPOSUIC OPC!" lens means for focusing iight passing along7 said optical i ture; axes from said scene as an image on the surface ot' lens means for focusingy light passing along said optical Said phorogensigive material; and G7485 from Said SCP-HC S HU mel 0H the SUYHCC Of means for causing said lens means to scan said scene in Said PhOLOSCUSVC mfitl; and synchronism with the movement of said photos/:insimeans fOr Causing Said 16H5 mCmS l0 502m Sad SCCH@ tive material past said exposure aperture to maintain in SYHCllYOUSm With lll@ ltlOVCmem Of Said Photo' said image stationary with respect to said photesensisensitive material past said exposure aperture to main tive margal tain said image stationary with respect to said photo- Regms @giebt l Smmefmmal' c il" urnreo .sr/tres rameurs y a. .t compact photographie camera including .x housinD I I I defining a generally rectangular volume having a minor 19476568 2/1934 Wafmlfiham 5S- E6 depth dimension substantially smaller than major length 3,259,448 7/1966 WlltlSJ Si Hl 352-e/4 and width dimensions thereof; 3,366i024 H1963 Siam 95-64 l means defining an elongated focal plane eXpOSLli'C tlpCf- 3;-, 25821194 6/1954 Ogenbufgll 8gb-Z4 ture eccentrically positioned within said housing and 2,966,696 l2/l960 Ulm-@ill @t Ill. 95-l5 lyingy in a plane parallel to the major dimensions of w U W D Said Hangmat volume; NORTON ANSHER, rrtmary examiner means for supporting a sheet of photosensitive material MCHAR M. SHEER, ASSI-Smm Examiner US. Cl. KR.

UNITED STATES PATENT DEFICE CERTIFICATE 0F CORRECTION Patent No. 3,478,662 Dated November 18, 1969 Inventor-(s) James G. Baker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 67, (appln. page 2, lines ll and l2) "photosensiitve" should be photosensitive;

Column 2, line 26, (appln. page 3, line l2) after "rating" insert --a preferred:

Column 2, line 6l, (appln. page 4, line 19) after "on" insert --the--7 Column 5, line 49, (appln. claim 9, line 26) "orthorgonal" should be --orthogonal.

Signed and sealed this Hlth day of If'iarch 1972.

(SEAL) Attest:

EDWARD M.ELETCHEE,JR. ROBERT GOTTSCI-ULLK Attestng Officer' Commissioner of Patents FORM F50-1050 (1D-69) uscoMM-Dc wave-969 

